A photo sent back of Pluto from NASA's New Horizons spacecraft is turning heads. The high-resolution image transmitted to Earth on Dec. 24 from the Long Range Reconnaissance Imager (LORRI) shows the dwarf planet's icy surface. However, look a little closer and you may see a strange and dark snail-like object.

Saturday, January 9, 2016, 3:29 PM - A photo sent back of Pluto from NASA's New Horizons spacecraft is turning heads.

The high-resolution image transmitted to Earth on Dec. 24 from the Long Range Reconnaissance Imager (LORRI) shows the dwarf planet's icy surface. However, look a little closer and you may see a strange and dark snail-like object.

The object in the photo is most likely a dirty block of ice "floating" on top of solid nitrogen, which is denser, according to NASA. It has been dragged to the edge of a convection cell. The view is of Sputnik Planum's centre, the icy plain to the left side of Pluto's 'heart.'

Sputnik Planum is not completely flat, with its surface separated into cells or polygons 16 to 40 km wide. Scientists believe the pattern of the cells stem from the slow thermal convection of the ices that fill Sputnik Planum. There is a reservoir of solid nitrogen, which in some places is several kilometres deep. It is warmed at depth by Pluto's modest internal heat. As it warms it rises up in great blobs and then cools down and sinks again to renew the cycle.

"This part of Pluto is acting like a lava lamp," said William Mckinnon, deputy lead of the New Horizons Geology, Geophysics and Imaging team, from Washington University. "If you can imagine a lava lamp as wide as, and even as deeper than, the Hudson Bay."

Computer models show these blobs of overturning solid nitrogen can slowly merge over a period of millions of years.